XIO2001: Power-Up Sequence

Shota Kobayashi

Prodigy 30 points

Part Number: XIO2001

Hi Team,

Please tell me about the Power-Up Sequence of the XIO2001.

In our design, PERST# transitions to Hi for a short period of time (1.9V@110us) while +1.5V and +3.3V are rising.

The waveform is as follows.

We think it is difficult to fix this problem, but does this cause XIO2001 to malfunction?

Best Regards,

Kobayashi

11 months ago

0 David Waier 11 months ago

TI__Genius 12621 points

Hi Shota-san,

The recommended action is to follow the power-up sequence outlined in data sheet section 6.12.1. Has a malfunction been observed using this implementation on your board, or is this design still in a simulation stage?

Best,
David

0 Shota Kobayashi 11 months ago in reply to David Waier

Prodigy 30 points

Hi David,

Thank you for your reply.

We are currently evaluating the board, but no malfunction has occurred.

If a malfunction occurs, what kind of phenomenon can be considered from this waveform?

Best Regards,

Kobayashi

0 David Waier 11 months ago in reply to Shota Kobayashi

TI__Genius 12621 points

Hi Shota-san,

The spike in PERST# would be a likely cause for this; however, asserting PERST# again before applying REFCLK should be sufficient to allow the device to correctly power-up.

Best,
David

0 Shota Kobayashi 11 months ago in reply to David Waier

Prodigy 30 points

Hi David,

I understand the sequence. Thank you.

Please tell me one more thing.
Is there any problem that a voltage of +1.9V is applied to the PERST# pin while +3.3V and +1.5V are rising?
The zoomed waveform is shown below.

Best Regards,

Kobayashi

+1 David Waier 11 months ago in reply to Shota Kobayashi

TI__Genius 12621 points

Hi Shota-san,

Per PCI Express specification, PERST# is required to be asserted for 100ms after the application of power. It is difficult to say if there will be a problem while VDD_33 is not yet stable, but PERST# is again re-asserted shortly after for > 100ms, which should be sufficient.

Best,
David

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XIO2001: Power-Up Sequence